The invention relates to an apparatus for filtering the air used in spinning machines and installations as well as other textile industries to clean it from fibers, dust etc. The filtering system includes a rotating filtering drum which is mounted to rotate about a horizontal axis and through which air flows from the outside to the interior.
Filter systems of this type are often used in the textile industry, for example to filter the exhaust air from machine rooms in a continuous manner, especially to filter out fibers and dust such as enter the air in large quantities in such factories, although other applications are possible. Generally such filtering drums are relatively large and heavy because the quantities of air which must be cleaned are very large. Thus it is not a simple matter to construct bearings for such drums which can stand up to the very large weight and the possibility of soiling and which produce a problem of positioning due to the fact that at least one end of the drum is usually open.
In a known apparatus of this type (German Offenlengungsschrift No. 1,607,728) the filtering drum has a shaft affixed to the center of the closed end of the drum and mounted in an associated bearing and provided with a gear for rotary driving while the open end of the drum is carried on two rollers at its circumference. The bearing for the shaft as well as the carrier rolls are all located external to the drum itself, i.e., in a space which is filled with uncleaned air so that the mechanical devices, i.e., the carrier rollers and the bearings, etc., are exposed to the presence of fibers, dust, etc., and thus are subject to soiling and the associated wear and tear and must be cleaned very often or will begin to offer great resistance to the motion. While it would be possible to mount the bearing at the closed end of the drum within a housing having a rotary seal, this would increase the constructional expense and would make it difficult to cool the motor if the motor was also included in the housing.
In another known apparatus (French Pat. No. 1,231,871,) the drum is also carried on external bearing and carrier rolls. However, in this case, the electrical motor is located in the cleaned air current and drives the drum by means of a pinion which engages an internal rack at the open end of the drum. Thus the electric motor may be cooled with clean air but the very large circular rack which must be machined to exact tolerances is very expensive and thus substantially increases the total expense of the filtering system. Furthermore, the external bearings are subject to the soiling alluded to hereabove and all of the disadvantages resulting therefrom.